Forget about those nasty, negative political ads. Think "cool" instead.

New research suggests our understanding of the state of "coolness" can be a powerful force, urging us to emulate others we regard as cool. Remember James Dean as the distant, mysterious, devil-may-care Jett Rink in the movie "Giant"? He was really cool, with his rebellious, smoldering outsider image. But that was then, this is now.

Today, it's Justin Bieber, the nice guy next door. Never mind the dark shades of yesteryear; nice is in now.

At least that's the conclusion of a team of scientists at several universities who have spent years trying to figure out exactly what we mean by the word "cool." That may sound unworthy of serious scientific research, but public perceptions of others, particularly those with a high sociological profile, can influence attitudes ranging from joining a gang to quitting smoking and even voting.

Most likely, voters will see one candidate as cooler than the other, and the coolest guy will probably win. Not that the state of coolness is the only factor in what seems like an endless political season, but in the end we want our candidate to be the kind of person we want to take home to meet the family. And today, that's cool -- defined in the study as "friendliness, personal competence, and trendiness."

"If we are on the right track, it (coolness) could be used as a leverage to increase pro-social behavior and decrease antisocial behavior," social psychologist Ilan Dar-Nimrod of the University of Rochester Medical Center, lead author of the study, said in a telephone interview.

"Look at smoking, for example," he said. In the movies, it's always the "cool" actor who lights up a cig, the kind of character Dar-Nimrod perceives as "sort of an outsider and a menace to society."

But that perception may be outdated. Maybe if the likeable characters in the movie quit smoking it would boost the anti-smoking movement -- because likeability is what's considered cool today. At least according to this research.

The study began several years ago when Dar-Nimrod was a doctoral candidate in psychology at the University of British Columbia. He and a fellow student, Ian Hansen, coauthor of the study published in the Journal of Individual Differences, were driving home from a movie when they got into an argument.

Was Steve Buscemi, who played the scary kidnapper in the movie "Fargo," cool?

"Ian thought he was," Dar-Nimrod recalled. "I had a problem with that evaluation because he was so unattractive and seemed such a weasel."

That little disagreement showed that neither of them really knew what the word "cool" meant, so they decided to find out.

"But we found that there really was no empirical research on what cool is," he said. "So we picked up where the sociological literature left off and we tried to actually look at what people evaluated as cool, and what they evaluated as uncool."

That led to three multi-year research projects involving nearly 1,000 mostly college-age residents of the Vancouver region in western Canada. Participants either listed the qualities they considered cool, or rated others on the coolness scale, or were evaluated themselves by others who presumably knew whether they were really cool.

Patterns in the answers enabled the researchers to better define the word. For example, participants in one of the three studies used 154 adjectives to rate various personality traits they regarded as cool. Those words were grouped in 11 categories (the words social and popular became friendly, and fun, partyer became hedonist.)

Friendly, personal competence and trendy far outranked all the other categories, with emotionally controlled and hedonist at the bottom.

Among these participants, Bieber outranks James Dean's "Rebel Without a Cause" by a huge margin.

"Adjectives that reflected positive undefined elements were common, but adjectives that reflect the kind of coolness described in previous scholarly work such as rebelliousness, roughness and muted emotions were not," the study concludes.

Even Dar-Nimrod said he would have been shocked at that finding when he was a kid.

"I got my first sunglasses when I was about 13," he said. "There wasn't a cooler kid on the block for the next few days. I was looking cool because I was distant from people. My emotions were not something they could read. I put a filter between me and everyone else. That, in my mind, made me cool."

Today, he added, "being nice is considered cool."

His research in this area is just beginning, he said, and that's fortunate because work in this field is limited. Most of the participants were young, white and female. A more diverse group might produce a different definition.